Effect of γ -Irradiation on the Dielectric and Conductivity Properties of Nano-Wollastonite

Abstract

Nanocrystalline porous CaSiO 3 ceramic powders have been synthesized by a novel low-temperature initiated self-propagating, gas-producing solution combustion method. Single phase β -CaSiO 3 (Wollastonite) is formed by calcination at 900°C for 3 h. The crystallization and phase formation temperatures in this method are found to be lower compared to the powder obtained via solid state reaction method. The powder is characterized by powder XRD (X-Ray Diffraction), and crystallite sizes are evaluated using Scherrer's formula as well as from TEM (Transmission Electron Microscopy). The Wollastonite powder is exposed to 60 Co γ -radiation to accumulated doses of 1, 3, and 5 KGy and low-frequency (10 2 –10 6 Hz) dielectric measurements are carried out before and after irradiation. The dielectric conductivity is estimated from the dielectric constant and loss tangent. Exposure to γ -radiation results in substantial modification in the properties of the ceramic powder due to changes in the porosity of the material. The correlation between dielectric and conductivity properties is discussed in relation to porosity effect.